Vol. 280, Issue 3, E518-E527, March 2001
Increased bone turnover is associated with protein and energy
metabolism in adolescents with sickle cell anemia
Maciej S.
Buchowski1,3,
F. Alexander
de la Fuente1,
Paul J.
Flakoll4,
Kong Y.
Chen3, and
Ernest A.
Turner2
1 Center for Nutrition and Department of Family Medicine,
and 2 Comprehensive Sickle Cell Center, Meharry Medical College,
Nashville 37208; and Departments of 3 Medicine and
4 Surgery at Vanderbilt University Medical Center,
Nashville, Tennessee 37232
Contribution of bone turnover to the hypercatabolic state observed
in sickle cell anemia is unknown. We examined the association between
markers of bone turnover and basal rates of whole body protein turnover
and energy expenditure in 28 adolescents with homozygous sickle cell
anemia (HbSS) and in 26 matched controls with normal phenotype (HbAA).
Whole body protein breakdown and synthesis were measured using a stable
isotope of [15N]glycine, resting energy expenditure was
measured by whole room indirect calorimetry, and the rate of
pyridinoline cross-link (PYD) excretion in urine and fasting serum
levels of the type I procollagen carboxy-terminal propeptide (PICP)
were measured with commercial kits. Urinary PYD and serum PICP were
significantly elevated in HbSS patients. The increase in procollagen
synthesis, indicated by high levels of PICP, was significantly
correlated with increased whole body protein synthesis. The increase in
type I collagen degradation, indicated by high PYD excretion, was
significantly correlated with increased protein breakdown. We conclude
that increased rates of bone turnover contribute to the increased rates of protein turnover and energy expenditure observed in adolescents with
homozygous sickle cell anemia.
sickle cell disease; protein turnover; energy expenditure; bone
remodeling
